1. Field of the Invention
This invention relates to a glow plug for accelerating the ignition of fuel in a combustion chamber in a diesel engine.
2. Description of the Prior Art
A glow plug comprises a heater which projects into the combustion chamber of the engine. A filament disposed within the element is heated when the supply voltage from a power source is applied to the filament. The power source can be, for example, a conventional vehicle battery which is also used to energize a starter for the engine. The glow plug facilitates diesel engine starting by raising the temperature of the heater from ambient temperature to a temperature sufficiently high to create a hot spot in the combustion chamber to ignite incoming fuel. Therefore, an operator of the engine must wait a relatively substantial period of time, i.e., a preheat time period, before the glow plugs in the engine have been sufficiently heated to facilitate diesel engine starting. Because the battery is a source of power for the starter and other equipment as well as the filament, the voltage level of the battery fluctuates. A decreasing battery voltage further lengthens the preheat time period.